I'd respectfully submit that the extra insurance is largely, if not wholly, illusory.

In support, let's consider a reverse scenario. Let's say I take my stock 996/997TT and put 87 octane in it. What happens? I will bet you a 996 turbo that nothing happens -- at least nothing noticeable. In fact, I bet you could run a track day with it. Would it be slower? Probably, the ECU would adjust.

So now going back to 93 octane, what insurance would 2 points of octane buy given that the car would almost undoubtedly run on 87? The insurance is provided in the proper combustion chamber shape, engineering for a low intake temp charge, and sophisticated engine computer control. I assert that it's not provided by 2 points of octane.

But even if you have a scenario where the car isn't detonating on 93, but it is detonating on 91, you are an insignificant cylinder head temperature away from not detonating both octanes.

100 octane is a different animal.

 

Thanks Wes. Great talking to you today.

For those that don't know Titan, they're an outstanding shop that I will be using for my Porsche build. They know how to do it the right way, and Wes knows his stuff.

 

Just rehashing an old thread.

The original question was not really answered, although a lot of good data was provided.

Has anyone dynoed their car running 91 octane file and fuel? What is the expected max for fuel of this poor quality?

Also Dr.J claims 35 whp for his turbo setup per .1 bar, but is this true at any fuel octane. Surely this isn't the case when you go from VP109 to shell 91?

 

On 91 I would not go past .9 bars. On 93 1.1 is the absolute limit. Only on C 16 will I turn it up to 1.5.

I may move back to California someday, but to be honest I would not build a car w/ GT turbos and reliant on good gas if I lived there.

 

Todd K can tune VP 109 for 1.6bar.

 

This is pretty conservative Sean. Many are running 1.3+ on 93. 1.5+bar on VP109.

 

Sean keeps turning the boost up in his car until he hears the engine popping.

 

I run 1.3bar MAX on pump gas (93oct), but then again I have VERY little timing and a good amount of fuel so I know she is safe.

 

Ok, lets look at this another way. Forget what Bar you run on 91, lets just see what power or times you are putting down on straight 91 octane only. Trap speeds, 60-130's or dyno numbers. What does a tuned 996tt put down on 91 octane, using whatever 24/18's, 16/24's, 16/16g's.

As powell stated, you can run more bar depending on your tuning.

 

The original point of my first post was an answer to this question. How much power can you make using x octane is a non-question -- the simple answer is how ever much you want to make. I've seen 3.0L turbocharged motors make 860 at the ground on 91. Undoubtedly they could make 1000 or any other obscene number. (Also, there seems to be a perception that higher octane fuels make more HP when, in fact, the exact opposite is true)

The more probative question is how much power can reliably me made on 91 octane? That question was batted around on the previous pages.

 

The days of making huge amounts of money are long gone for me....I am just a little old teacher getting by on his salary, so I cannot afford an engine build.

At the risk of being trite, I would rather be safe than sorry.

Anyway, I think I can run a 5.5 at 1.5 using C 16 on my new set up.

She should be done by Monday.

Back to the difference between CA 91 and Tx 93, I have been told by several very knowledgeable people (Todd K is one, another is from the Mustang community) that the difference is, in fact, fairly large. My power levels are contingent upon the boost levels I run and I am not willing to go over 1.1 on pump.

 

but it really wasn't. No one has provided info directly stating, "I put down 5xx awhp/5xx awtq on a mustang dyno" or "I ran a 6.9 60-130 on 91" or " my trap speed was 12xmph"

 

Garret at GIAC told me that Cali 91 is like east coast 87.

 

Because such info is completely worthless without context.

Your question is analogous to "what color can I paint my car?" That's a non-starter. "What color would work with my car?" Now we can have a discussion with worthwile info. (see previous pages)

 

you're telling me, that knowing how much power a car with known hardware running 91 octane can make is irrelevant? Not so. No less irrelevant that what a car using C16 or VP109, or meth is. This data tells you how good the tuning and hardware combination is. Very relevant.

additionally, go look at the perofrmance data on the sticky for our cars and compare that to some factory supercars listed there as well. You will see that the factory cars did not have some race tune running C16..lol. They run pump gas, usually 91-93. So in effect our times are not really comparable to factory cars no more than a dragster is when running race fuel, nitro methane, etc.

it is amazing to me that cars can have ***** on C16 and act totally neutered on pump gas.